Vapor-converter.



D. C. DAVIS.

VAPOR CONVERTER.

APPLICATION FILED JUNE 16. I916.

Patented Apr. 15,1919.

WlTNESSES 0a W0 6. flay/'5 1 BY QQMA/ W517 ATTORNEY To all whom it may concern: 7

UNITED STATES PATENT OFFICE.

DAVID C. DAVIS, 0F WILKINSIBURG, IENNSYLVANIA, ASSIGNOR T0 WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

VAPOR-CONVERTER.

Specification of Letters Patent.

Patented Apr. 15, 1919.

Application filed J um: 18, 1916. Serial No. 104,073.

Be it known that I, DAVID C. DAVIS, a citizen of the United States, and a resident of WVilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Vapor- Co-nverters, of which the following is. a

specification.

My invention relates to vapor Converters, and it has for its object to provide apparatus of the character designated that shall embody effective means for positively preventing short circuit-ing, reverse-arcing and allied phenomena.

In the accompanying drawing, Figure, 1 is a side view, partially in section and partially in elevation, of a vapor converter of the metal-case type embodying a preferred form of my invention; Fig. 2 is a plan view of the shielding disk employed in the converter of Fig. 1; and Fig. 3 is a plan view of a modified form of shielding disk which may be employed in a like relation.

It is well known that, in the operation of vapor converters, there is a more or less marked tendency for failure of the negativeelectrode reluctance of an anode during periods when said anode is negative in polar ity, and consequently, inactive. A variety of causes have been assigned for this undesirable phenomenon, chief among which may be cited the impact of a mercury glob vule upon an anode during a period of inacsaid mechanical converter serving to open.

the lead to each anode in the vapor con-= verter during a period of inactivityof said anode.

By my invention, I provide means, principally within the container, whereby each anode is completely inclosed, during its periods of inactivity, and thereby completely shielded from flying mercury globules and from the cathodic electron emission. When, however, the anode becomes positive in potential, said shielding mechanism is opened to'provide a free and direct path between the anode and the cathode for the passage of said electron emission and the resultant power arc.

For a more detailed understanding of my invention, attention is directed to Fig. 1 of tainer of a vapor converter of the metalcase type is shown at 4:. The container 4 is provided with a liquid cathode 5 and With solid anodes 6 and 7 of usual and well known construction. The anodes 6 and 7 are insulated from the cover off the container 4 by any suitable means and are connected, respectively, to the terminals of the secondary winding 8 of a supply transformer 9. The cathode 5 is connected to the mid-point of the secondary Winding 8 through the material of the case and through a load 10, as is-usual in the art. A keen-alive are may be struck to the oathode 5 by a starting and maintaining anode 11 depending from the core 12 of a solenoid 13, all of which is adapted to be energized from a direct-current source 14: by the closure of a suitable switch 15.

shielding member surrounds each of the members 6 and 7 and preferably takes the form of a cylindrical casing 16 of segmenthe accompanying drawing wherein the contel cross-section, insulated and closed at its 1 upper end but open at its lower end. A disk 17 preferably composed of insulating material, such, for example, as quartz or porcelain, is mounted to rotate in a plane closely adjacent to the open ends of the shields 16 16 and said disk is provided with an opening or openings adapted to register with the open end-s of said shields 1616 when said disk is rotated. The disk 17 is shown in Fig. 2 as having. an opening 18, the lower ends of the anodes 16-16 being indicated by dotted segments.

In the operation of the vapor converter,

it is desired that the disk 17 be synchropurpose, I provide a synchronous motor at 19, said motor comprising a fixed armature member 2020, exterior to the converter casing and energized from the secondary winding 8, and a field-magnet structure 21 disposed within the container and mounted on the upper end of a hollow shaft 22 supporting the disk 17 by means of a spider 23. A ring 24, preferably composed of insulating material in order to minimize eddy currents, is disposed between the armature structure 20 and the'field-magnet structure 21 in order to maintain a vacuum within the container 4. Said ring is preferably surmounted by a disk 25 of conducting material provided with an upwardly extendinghollow' member 26 interposed between the. solenoid 13 and 5 the core member 12. The members 25 and 26 are preferably constructed of non-magnetic metal in order that't-he magnetic flux of said solenoid 13 may act efiectively upon the core member 12. Direct current from the keep-alive battery 14:, after passing through the solenoid 13, flows through the materlal of the disk 25 and thence into a sleeve 27 making contact therewith and supported upon the upper end of the rotating structure. From the sleeve 27, the direct current traverses the winding of the fieldmagnet structure 21 and thence flows to the keep-alive electrode 11 through. a suitable brush 28. The lower end. of the shaft 22 rests upon a ball bearing 29 which should have certain portions thereof constructed of graphite for effective lubrication under the severe operating conditions of relatively I high speed and of high vacuum. The fixed 25 or lower race-way ofthe bearing 29 is preferably formed in the shape of a deep upwardly extending trough so that it may catch and maintain condensed mercury, thus assisting in cooling the bearing.

Having thus described the construction of a vapor converter embodying my. invention, the operation is as follows. After energizing the main supply circuit, the switch 15 is closed to energize the solenoid 13 and strike a keep-alive arc at the lower end of the electrode 11. The synchronous motor 19 is brought up to synchronous speed in any well own manner but that method of starting which I have found particularly adapted to the machine in question is as follows: The armature structure 20 is rotated by hand, or by any other means, at substantially synchronous speed, in either direction for a single-phase motor, as. shown, but against the direction of rotation of the rotating field in a polyphase motor and, in this way, the rotating field thereof is caused to remain stationary in space; that is to say, it looks into synchronism with the stationary field magnet 21. 7 Upon slowly bringing the armature structure to rest, said locked relation is maintained and the field-magnet structure 21 is brought up to synchronous speed. This particular method of starting a synchronous motor is well known in the art and does not form-a part of my invention and therefore need not .be described or illustrated in f .;further detail. The disk 17 is now rotating at synchronous speed and the location of the so penin'g 18 therein with respect to an anode,

v'henit is de sired that said anode be active, y be adjusted by circumferential rotation earmature structure 20 by any suitable means,-'such, forex-ample, as a handle 30. Tli'econverternow-ilcontinues to operate, en

tirely inclosing each anode during its periods of inactivity and providing a direct and effective electron path between each anode and the cathode when it is desired that said anode be active.

By the operation of the handle 30, the portion of each alternating current wave that is to be rectified and passed to the load circuit may be adjusted, thus permitting control in the voltage and energy of the output of the converter.

If it be desired to alter the portion of each half-cycle that is to be rectified, I may provide means for adjusting the length of time during which each anode is exposed to the cathodic electron emission. As shown in Figs. 1 and 2, said means comprises shutter members 3131 and 32-32 mounted adjacent to the lower ends of the shields 16. Said shutter members are mounted 011 scissor links 33-33 so that they are capable of movement toward and away from each other to affect the period during which the anodes are exposed. The scissor links are connected to the core member 34 of a solenoid 35 mounted exterior to" the container so that they maybe adjusted in opposition to a control spring 36 or other equivalent means.

With commercial frequencies, the necessary speed of the disk 17 is rather high if said disk is provided with but a single are opening. I may, therefore, employ a disk of the form shown in Fig. 3 wherein three are openings 18, displaced from each other by 120 are employed to coact with two anode shields displaced from each other by 180. The disk need therefore be driven at but one-third the speed of the disk shown in Fig. 2 to attain the same results. Obviously, by employing a larger number of suitably spaced openings, still lower speeds may be employed.

While I have shown my invention in its preferred form, it will be obvious to those skilled in the art that it is susceptible of various minor changes and modifications without departing from the spirit thereof and I desire, therefore, that only such linntations shall be placed thereupon as are imposed by the prior art or as are indicated in the appended claims.

I claim as my invention:

1. In a vapor converter, the combination with aperiodically active electrode, of mean for, entirely Shielding said electrode from the interior of the container during its periods of inactivity.

2. In a vapor converter, the combination with an electrode which is periodically active, of means for entirely shielding said electrode from the interior of the container durin inactive periods.

3. n a vapor, converter, the combination with a periodically active anode, of a shieldingmember surrounding the same and prosaid anode is entirely shielded from the interior of said converter during its periods of inactivity.

4. In a vapor converter, the combination with an anode, of a shielding member surrounding the same and provided with an arc exit, and means forclosing said exit during periods of inactivity of said anode.

5. In a vapor converter, the combination with an anode, of a cathode, means for causingelectron emission from said cathode, and means for mechanically cutting oif said electron emission from said anode during periods of negative polarity thereof and for permitting said electron emission to impinge upon said anode during periods of positive polarity thereof.

6. In a vapor converter, the combination with an anode, of a shielding memberfor' said anode provided with an arc exit, a disk mounted in front of said are exit and -pro-.

vided with opening therethrough adapted to register with said are exit, and means for synchronously rotating said disk so that one of said openings registers with said are exit when said anode is positive inpolarity and so that said are exit is closed by said disk when said anode is negative in polarity.

7. The method of preventing short circuitin in a vapor converter whichlcomprises.

entirely shielding the anodes from the cathodic electron emission during periods of negative polarity of said'anodes.

8. The method of operating a'vapor converter which comprises exposing an anode thereof to the cathodic electron emission during periods of positive polarity in said anode, and entirely shielding. said anode from said emission during periodsiof negative polarity in said anode.

- 9. The combination with a vapor converter, of adjustable shielding means therein arranged to permit the initiation of and to top current flow from each alternating current wave at any desired points therein, whereby that portion of each alternating supply wave which is to be rectified may be varied.

10. The method of varying the characteristics of the output of a vapor converter which comprises exposing each anode thereof to the cathode only when it is desired that said anode be active, and adjusting the phase of said times of exposure.

11. In a vapor-converter, the combination with means for periodically exposing an anode to the cathodic electronemission, of means for varying the duration of each exposure while maintaining the frequency thereof substantially constant.

12. In a vapor-converter, the combination with means for exposing an. anode to the cathodic emission solely when said anode is of positive polarity, of means for varying .the duration of'each such exposure.

In testimony whereof, I have hereunto subscribed my. name this 8th day of June 1916. I

DAVID c. DAVIS. 

